Flexible pipes currently used in offshore oil and gas fields for the transport of fluids underwater between the subsea wellhead and the surface facilities are designed to retain a circular cross-section when subject to external hydrostatic pressure. This is usually achieved by the inclusion of metallic layers which extend around and support a polymer fluid barrier layer and which resists collapsing under the external hydrostatic pressure. However, for deep water applications, the strength and the weight of the metallic layers required to resist collapse becomes a limiting factor in flexible pipe design.
Also, in these designs the innermost barrier layer is designed to contain the fluid or gas. Thus, when the pipe collapses or is squashed, the barrier wall will experience excessive localized over-bending, which can cause structural damage to the barrier layer and result in failure of the pipe.
Therefore, what is needed is a flexible pipe that can tolerate relatively high hydrostatic pressure yet eliminate the disadvantages of the metallic layers discussed above while avoiding potential structural damage to the barrier layer.